It is well known and understood by those who work with aquariums of any significant size that a filtering process of some kind is required to keep the water in habitable condition for the fish. On smaller fresh water aquariums such filtering may involve little more than a simple filter element associated with the water circulation and aeration system, frequently augmented with one or more scavenger type fish. On larger salt water systems and where delicate varieties of fish are involved, a more complex system has been developed, referred to as a wet/dry system in which water is skimmed from the top of the tank, subjected to a pre-filtering operation in which certain solids are removed, and is then diffused through a type of filtering element which operates in air with the contaminated water diffused through it in small droplets known in the art as a DLS (Double Layer Spiral) filter. The function of this DLS filtering element is to support the colonization of nitrifying bacteria which function to consume organic wastes dissolved in the water passing through the filter. This filter is used in combination with a protein skimmer which continually segregates a portion of the water from the pre-filter and removes certain dissolved organic material before it can enter the denitrification cycle (through the DLS filter). The use and function of protein skimmers is well known and understood the art.
To provide the kind of filtration described above, a housing of fairly large size is required. Such housings have, in the past, been assembled much the same as the tanks themselves with several separate members such as pieces of glass or plexiglass sealed together at the edges and the filter members inside and certain pipes and/or hoses connected to the housing. Such filter assemblies are large and heavy and are essentially a custom installation, hence, expensive. It has become apparent that there is a need for a filter assembly which incorporates the above described filtering system, but which is designed and packaged such that it can be conveniently marketed and shipped, and which can be easily installed by an aquarium owner.